Tissue treatment device and method

ABSTRACT

A controlled pressure device includes a reactor housing element, a reactor, and a cosmetic liquid or cream. The reactor housing element is configured to at least partially define an at least substantially air-tight enclosed volume around a tissue site when fixed in space in relation to the tissue site. The reactor is positioned in the enclosed volume and is configured to react with a selected gas found in air. The reactor consumes the selected gas within the enclosed volume. The cosmetic liquid or cream is also located in the enclosed volume.

This application claims priority to U.S. Provisional Application Ser.No. 62/248,422 filed on Oct. 30, 2015, the entirety of which isexpressly incorporated by reference.

BACKGROUND

The pores of the skin can become occluded with impurities. Negativepressure has been used to generate a partial vacuum to aid in removingimpurities from the pores. Negative pressure is a term used to describea pressure that is below normal atmospheric pressure. At roomtemperature and at sea level, a defined volume of air contains moleculesmoving in random directions, and these moving molecules exert a forcethat is equal to the normal atmospheric pressure of approximately 760mmHg (about 1 bar). Negative pressure has been achieved by removing airfrom an area of interest, for example at a tissue site via a suctionpump.

Devices for the generation of topical negative pressure at the surfaceof a person's skin have been used for many hundreds of years to treathumans. For example, the cupping technique, which relates to positioninga mouth of a rigid vessel containing hot air on a human's skin, is awell-known technique. Spring powered syringes and suction cups are othermechanical techniques that have been used for generating a partialvacuum on human tissue. In common with cupping, such other mechanicaltechniques have offered a limited topical negative pressure duration andlittle or no range of neutral to positive pressures. This is due todesign constraints and that the cupping technique and other mechanicaltechniques are not self-contained and can hinder a user's mobility.

To enable a more prolonged application of topical negative pressure,powered systems, which include a vacuum generation source such as apump, have been developed and many examples of such systems are usedtoday for skin treatments and restorative purposes like the temporaryremoval of wrinkles. Many of these systems, however, are not convenientfor users. Such known systems can be large, heavy, noisy, uncomfortable,and not simple for users to apply and initiate a controlled pressurecondition. Such known systems also rely on an outside power or vacuumsource to create topical negative pressure conditions.

SUMMARY

In view of the foregoing, a controlled pressure device includes areactor housing element and a reactor. The reactor housing element isconfigured to at least partially define an at least substantiallyair-tight enclosed volume around a tissue site when fixed in space inrelation to the tissue site. The reactor is positioned in the enclosedvolume and is configured to react with a selected gas found in air. Thereactor consumes the selected gas within the enclosed volume.

Another example of a controlled pressure device can include a reactorhousing element and a reactor. The reactor housing element is configuredto at least partially define an at least substantially air-tightenclosed volume around a tissue site when fixed in space in relation tothe tissue site, and the enclosed volume has a determined volume (DV).The reactor is positioned in the enclosed volume and is configured toreact with a selected gas found in air. The reactor consumes theselected gas within the enclosed volume. The reactor is configuredhaving a predetermined scavenging capacity (SC) for the selected gas.The controlled pressure device is configured to have a maximum leakagerate (LR) when affixed to a subject's skin for air entering the enclosedvolume. The controlled pressure device is also configured to a minimumwear time (MWT) and is configured according to the followingrelationship: SC>DV*(% of selected gas in air)+LR*(% of selected gas inair)*MWT.

In view of the foregoing, method of treating a tissue site includesremoving a release layer from a reactor housing element. The methodfurther includes placing the reactor housing element, a reactor and aliquid impermeable—air permeable membrane over the tissue site. Themethod also includes affixing the reactor housing element with respectto skin around the tissue site to define an at least substantiallyair-tight enclosed volume around the tissue site.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view of a controlled pressuredevice.

FIG. 2 is a schematic exploded perspective view of a controlled pressuredevice.

FIGS. 3 and 4 are schematic depictions of alternative reactorembodiments that can be used with the controlled pressure device shownin FIG. 1.

FIGS. 5-7 are schematic depictions of powered components that can beused with the controlled pressure device shown in FIG. 1.

FIGS. 8 and 9 are flow diagrams depicting a method of treating a tissuesite.

DETAILED DESCRIPTION

FIG. 1 depicts a controlled pressure device 10 including a reactorhousing element 14 and a reactor 16. The controlled pressure device 10can be used in conjunction with a cosmetic liquid or cream for tissuetreatment. For example, the controlled pressure device 10 can include orbe used in conjunction with a pad, which can be wetted or impregnatedwith a cosmetic liquid or cream, and will be hereinafter referred to asa cosmetic pad 18. The controlled pressure device 10 can be positionedat a tissue site 20 to enhance tissue treatment including, but notlimited to, wound healing, reduction of skin wrinkles, and other skinmaladies. The reactor housing element 14 is configured to at leastpartially define an at least substantially air-tight enclosed volume 22around the tissue site 20 when affixed in space in relation to thetissue site 20. FIG. 1 depicts the reactor housing element 14 in contactwith the tissue (e.g., skin) around the tissue site 20, however, thereactor housing element 14 can be fixed in space in relation to thetissue site 20 without being in direct contact with the tissue aroundthe tissue site 20. For example, an intermediate membrane or layer, suchas a skin contacting element 24 (FIG. 2), could be interposed betweenthe reactor housing element 14 and the tissue (e.g., skin) around thetissue site 20, although the reactor housing element 14 is fixed inspace in relation to the tissue site 20. The reactor 16 positioned inthe enclosed volume 22 reacts with a selected gas found in air andconsumes the selected gas within the enclosed volume 22. The cosmeticliquid or cream is also located in the enclosed volume 22.

With reference to FIG. 2, the controlled pressure device 10 can includesthe skin contacting element 24. The skin contacting element 24 includesa skin contacting side 30 that is adherable to a subject's skin and aninterface side 32, which is opposite to the skin contacting side. In theillustrated embodiment, the skin contacting element 24 is shown as aseparate element from the reactor housing element 14. In an alternativearrangement, the skin contacting element 24 can be provided as part ofthe reactor housing element 14, e.g., the skin contacting element 24 canbe integrally formed with the reactor housing element 14 or connectedwith the reactor housing element 14 at the manufacturing facility. Theskin contacting element 24 can be made from a thin sheet-like membrane,for example using a roll-to-roll process. In the illustrated embodiment,the skin contacting element 24 also includes openings 34 extendingthrough the skin contacting element 24 from the skin contacting side 30to the interface side 32. The openings 34 can be located over the tissuesite 20. In conjunction with a skin contacting gasket 36, the skincontacting element 24 is configured to provide a seal around the tissuesite 20 to allow for topical negative pressure to be applied at thetissue site 20. If desired, the skin contacting element 24 can includean opening that is larger than each of the openings 34 depicted in FIG.2. In this example, the opening 34 can be dimensioned to fit around thetissue site 20. The opening 34 in this example can be similarly shapedto the cosmetic pad 18 so that the skin contacting element 24 and theskin contacting gasket 36 provide a seal around the tissue site 20(FIG. 1) and the cosmetic pad 18. If desired, the skin contactingelement 24 need not include the opening(s) 34, and in this example, thecosmetic pad 18 can be positioned beneath the skin contacting side 30 soas to come in contact with the subject's skin at the tissue site 20.

Both the skin contacting side 30 and the interface side 32 are generallyflat or planar. In the illustrated embodiment, the interface side 32 isthe upper side of the skin contacting element 24 and the skin contactingside 30 is the lower side of the skin contacting element. Adhesive 38(depicted schematically in FIG. 2) can provided on the skin contactingside 30 to allow the skin contacting side 30 to adhere to the subject'sskin around the tissue site 20.

The skin contacting gasket 36 can be provided on the skin contactingside 30 of the skin contacting element 24 or simply be positionedbetween the skin contacting side 30 and the subject's skin. The skincontacting gasket 36 can be made from a hydrogel to further promotesealing around the tissue site 20 to promote the topical negativepressure at the tissue site 20.

A release layer 40 can be provided with the controlled pressure device10 to protect the skin contacting side 30 of the skin contacting element24. The release layer 40 can be similar to known release layers andinclude an upper side 42 that is releasable from the skin contactingside 30 of the skin contacting element 24. The release layer 40 alsoincludes a lower surface 44 opposite the upper side 42. As mentionedabove, the reactor 16 reacts with a selected gas found in air andconsumes the selected gas within the enclosed volume 22. In someembodiments, the release layer 40 can provide an air-tight barrier suchthat air is precluded from access to the reactor 16 until after therelease layer 40 is removed from the skin contacting element 24. Inembodiments where the skin contacting element 24 may not be provided,the release layer 40 can cooperate with the reactor housing element 14in a similar manner, and the release layer 40 can provide an air-tightbarrier such that air is precluded from access to the reactor 16 untilafter the release layer 40 is removed from the reactor housing element14.

With reference back to FIG. 1, the reactor housing element 14 at leastpartially defines the enclosed volume 22 around the tissue site 20 whenfixed in space in relation to the tissue site 20. With reference to theembodiment depicted in FIG. 2, the reactor housing element 14 cooperateswith the skin contacting element 24 to at least partially define theenclosed volume 22 (see FIG. 1) around the tissue site 20, for example,when the skin contacting side 30 of the skin contacting element 24 is incontact with and adhered to the subject's skin and the reactor housingelement 14 is affixed to the skin contacting element 24. The reactorhousing element 14 can be formed with a hood 50 and a lower peripheralsection 52 that at least partially surrounds the hood 50. In theillustrated embodiment, the lower peripheral section 52 entirelysurrounds the hood 50, which is raised in relation to the lowerperipheral section 52 so as to define the enclosed volume 22 around thetissue site 20. The reactor housing element 14 can also be formedwithout the hood 50, i.e., the reactor housing element 14 couldinitially be planar. Similar to the skin contacting element 24, thereactor housing element 14 can be made from a thin sheet-like membrane,for example using a roll-to-roll process. The reactor housing element 14can be made from a flexible material that is similar to or the sameflexibility as the skin contacting element 24, which allows thecontrolled pressure device 10 to conform to the skin around the tissuesite 20. When the reactor housing element 14 is affixed to the skincontacting element 24, the reactor 16 is located between the reactorhousing element 14 and the cosmetic pad 18 and the skin contactingelement 24. Since the reactor housing element 14 is made from a flexiblematerial in this example, the section of the reactor housing element 14that is not in contact with the skin contacting element 24 is raised oroffset from the tissue site 20 so as to form the hood 50.

The reactor housing element 14 can be made from a material that is airimpermeable so that air is precluded or greatly inhibited from enteringinto the enclosed volume 22 as the reactor 16 consumes a selected gaswithin the enclosed volume thus reducing gas pressure within theenclosed volume. The reactor housing element 14 could also be made frommaterials that are impervious to particular gasses (e.g., oxygen) andpervious to other gases (e.g., nitrogen). The reactor housing element 14can be formed of a material that is at least partially gas permeable forselected gasses (e.g., nitrogen gas permeable) to exhaust the selectedgas from the tissue site 20 to atmosphere. The reactor housing element14 includes a lower surface 56. An adhesive 58 (depicted schematicallyin FIG. 2) can be applied to the lower surface 56. With reference toFIG. 1, the lower surface 56 contacts the skin around the tissue site 20and the adhesive 58 adheres the reactor housing element 14 to the skinaround the tissue site 20. A reactor housing element gasket 60, whichcan be a hydrogel gasket similar to the skin contacting gasket 36described above, can be provided between the lower surface 56 of thereactor housing element 14 and the skin to further seal between thereactor housing element 14 and the skin to preclude air migrationbetween the interface between the lower surface 56 the skin.

With reference to FIG. 2, the reactor housing element 14 can affix tothe interface side 32 of the skin contacting element 24 providing asubstantially air-tight seal between the reactor housing element 14 andthe skin contacting element 24. The adhesive 58 applied to the lowersurface 56 can affix the reactor housing element 14 to the skincontacting element 24. The reactor housing element gasket 60 can beprovided between the lower surface 56 of the reactor housing element 14and the interface side 32 of the skin contacting element 24 to furtherseal between the reactor housing element 14 and the skin contactingelement 24 to preclude air migration between the interface between thelower surface 56 of the reactor housing element 14 and the interfaceside 32 of the skin contacting element 24.

The reactor 16 is positioned in the enclosed volume 22 and is configuredto react with one of more selected gases (e.g., nitrogen, oxygen, carbondioxide) found in air to consume the selected gas within the enclosedvolume 22, which can reduce gas pressure within the enclosed volume 22.The reduction in gas pressure within the enclosed volume 22 can resultin a partial vacuum being formed in the enclosed volume 22, which canresult in a downward force (in the direction of arrow 70) being appliedto the hood 50 of the reactor housing element 14. The reactor housingelement 14 can be configured such that the downward force (in thedirection of arrow 70) on the hood 50 (or the top of the reactor housingelement 14) results in an outward force (normal to the direction ofarrow 70) on the lower peripheral section 52. Since the reactor housingelement 14 is affixed to the skin contacting element 24, which isadhered to the subject's skin, or directly to the skin (see FIG. 1) theoutward force in the direction normal to arrow 70 can result in smallstrains and stresses being applied to the patient's skin around thetissue site 20. These strains and stresses being applied to thepatient's skin can be beneficial for the introduction of the cosmeticliquid or cream impregnated within the cosmetic pad 18 as well asproviding a massaging effect of the skin. Where the reactor housingelement 14 is made from a relatively more rigid material with respect tothe skin contacting element 24, for example, flexible regions 74 can beprovided in the lower peripheral section 52 to facilitate outwardmovement of the reactor housing element 14 with respect to the tissuesite 20 to allow for the small strains and stresses to be applied to thesubject's skin at the tissue site 20.

The reactor 16 is positioned in the enclosed volume 22 and is configuredto react with the selected gas (e.g., nitrogen, oxygen, carbon dioxide)found in air. As the reactor 16 consumes the selected gas within theenclosed volume 22, the gas pressure within the enclosed volume 22 isreduced. For example, where the reactor 16 consumes oxygen, there can bean approximate 20% reduction from atmospheric pressure in the enclosedvolume 22. An example of a reactor 16 that can be used in the controlledpressure device is described in US 2014/0109890 A1, which isincorporated by reference herein. US 2014/0109890 A1 describes an oxygenbased heater; however, the oxygen based heater described in US2014/0109890 A1 can be used as the reactor 16 to consume oxygen withinthe enclosed volume 22 thus producing a partial vacuum within theenclosed volume 22. In this example, the reactor 16 includes a reducingagent, a binding agent on a reactor substrate 80 and an electrolytesolution, which can be provided in an electrolyte impregnated pad 82.The reducing agent on the reactor substrate 80 can be zinc, aluminum, oriron, for example.

As mentioned above, the release layer 40 can operate as an air-tightbarrier such that the selected gas (e.g., nitrogen, oxygen, carbondioxide) is precluded from access to the reactor 16 until after theair-tight barrier, which in this instance is the release layer 40, isremoved from the controlled pressure device 10. Alternatively, thecontrolled pressure device 10 can include a package, which is shown inFIG. 2 as including an upper layer 94 and a lower layer 96. The upperlayer 94 affixes to the lower layer 96 enclosing the reactor substrate80 in between the upper layer 94 and the lower layer 96 so as to providean air-tight seal so that the selected gas is precluded from access tothe reactor 16. In this example including the package, the upper layer94 or the lower layer 96 can operate as an air tight barrier in thatremoval of the upper layer 94 from the lower layer 96, or vice versa,allows the selected gas access to the reactor 16 so that the selectedgas can be consumed by the reactor 16. Alternatively, at least one ofthe layers (the lower layer 96 in the illustrated embodiment) caninclude openings 98 and a seal layer 102 can be affixed in an air-tightmanner to the lower layer 96 covering the openings 98. Removal of theseal layer 102 from the lower layer 96 exposes the reactor 16 to theselected gas, which allows the reactor to consume the selected gaswithin the enclosed volume 22. The surface area of the openings 98 canbe appropriately sized to control the flow of the selected gas throughthe openings to sustain the chemical reaction of the reactor 16 to thedesirable time limit for maintaining topical negative pressure on thetissue site 20 for the desired duration. Moreover, multiple seal layers102 can be provided so that removal of one or a selected few of the seallayers (while other seal layers are still affixed to the lower layer 96)can also be provided to limit the flow of the selected gas toward thereactor 16. Additionally, to further control the pressure within theenclosed volume, the controlled pressure device 10 can include apressure relief valve 106 on the reactor housing element 14. Thepressure relief valve 106 can allow for selected communication betweenthe enclosed volume 22 and ambient. The pressure relief valve 106 can beoperated when a predetermined pressure differential exists between theenclosed volume 22 and ambient. Moreover, the pressure relief valve 106can be configured to open when the temperature within the enclosedvolume exceeds a desired predetermined temperature.

To also further control the pressure within the enclosed volume 22, thecontrolled pressure device 10 can be configured to allow an operator tochange the size of the enclosed volume 22 while the reactor 16 consumesthe selected gas in the enclosed volume, thus varying the gas pressurewithin the enclosed volume 22. For example, a tab 110 can be affixed tothe reactor housing element 14, and the operator can pull the tab 110 tomove the reactor housing element away from the tissue site 20. In FIG.2, the tab 110 is affixed to the hood 50. When the enclosed volume 22 isunder negative pressure, the hood 50 will tend to travel toward thetissue site 20. By pulling on the tab 110, the hood 50 can be moved awayfrom the tissue site 20 and air can enter the enclosed volume 22, forexample by leaking past the gasket 36 or a small pre-configured leakagepath can be provided. Air entering the enclosed volume 22 can increasethe pressure within the enclosed volume 22 until the selected gas (e.g.,oxygen) is consumed by the reactor 16. Such a configuration can allowfor a cycling of pressure in the enclosed volume 22.

The controlled pressure device 10 can also be packaged such that thereactor housing element 14 and the reactor 16 are packaged separatelyfrom the skin contacting element 24, for example. In such an embodiment,a reactor housing element release layer 120 can be provided. The reactorhousing element 14 release layer 120 can be similar to the release layer40 having an upper side 122 that is releasable from the lower surface 56of the reactor housing element 14. The reactor housing element releaselayer 120 further includes a lower surface 124 that is opposite to theupper side 122. The reactor housing element release layer 120 can alsobe affixed to the lower layer 96, so that removal of the reactor housingelement release layer 120 from the reactor housing element 14 results inremoval of the lower layer 96 from the upper layer 94, thus exposing thereactor 16 to air. Alternatively, the reactor housing element releaselayer 120 can be affixed to the seal layer 102 such that removal of thereactor housing element release layer 120 from the reactor housingelement 14 results in removal of the seal layer 102 from the lower layer96, thus exposing the reactor 16 to air via the openings 98 provided inthe lower layer 96.

Where the controlled pressure device 10 is packaged where the reactorhousing element 14 and the reactor 16 are separate from the skincontacting element 24, an upper skin contacting element release layer(not shown) can be provided. The upper skin contacting element releaselayer can be similar to the release layer 40. Alternatively, no upperskin contacting element release layer need be provided.

The controlled pressure device 10 further includes a liquidimpermeable-air permeable membrane 150 interposed between the reactor 16and the cosmetic liquid or cream, which is impregnated in the cosmeticpad 18 in the illustrated embodiment. The size (area) of the liquidimpermeable-air permeable membrane 150 can depend on the location of theliquid impermeable-air permeable membrane 150 within the controlledpressure device 10. If the cosmetic liquid or cream were to come incontact with the reactor 16, the chemical reaction of the reactor 16when coming in contact with the selected gas may be detrimentallyimpacted. As such, the liquid impermeable-air permeable membrane 150allows air flow within the enclosed volume 22 while precluding thecosmetic liquid or cream from coming into contact with the reactor 16.

The liquid impermeable-air permeable membrane 150 can be located indifferent locations on the controlled pressure device 10. In one exampledepicted in FIG. 2, the liquid impermeable-air permeable membrane 150can be located between the reactor substrate 80 and the lower layer 96making up the air-tight package for the reactor 16. So, once the lowerlayer 96 (or the seal layer 102) is removed, air can gain access to thereactor 16, but the cosmetic liquid or cream would be precluded fromtraveling through the liquid impermeable-air permeable membrane 150. Inanother example, the liquid impermeable-air permeable membrane 150 canbe located between the lower layer 96 (or the seal layer 102) making upthe air-tight package for the reactor 16 and the cosmetic liquid orcream, which can be impregnated in the cosmetic pad 18. More generally,and as depicted in FIG. 1, the liquid impermeable-air permeable membrane150 can be located between the reactor 16 and the cosmetic liquid orcream, which would be impregnated in the cosmetic pad 18. As depicted inFIG. 1, the liquid impermeable-air permeable membrane 150 can beconnected with the reactor housing element 14 and preclude the cosmeticliquid or cream from passing through the liquid impermeable-airpermeable membrane 150 while allowing air to travel through the liquidimpermeable-air permeable membrane 150 so that the selected gas can beremoved from the enclosed volume 22. If desired, the liquidimpermeable-air permeable membrane 150 could surround the reactor 16 andpreclude the cosmetic liquid or cream from passing through the liquidimpermeable-air permeable membrane 150 while allowing air to travelthrough the liquid impermeable-air permeable membrane 150.

In an embodiment where the reactor housing element 14 and the reactor 16are packaged separately from the skin contacting element 24, the releaselayer 40 can be removed from the skin contacting element 24. The skincontacting element 24 can be pressed against a subject's skin around thetissue site 20 and adhesive 38 on the skin contacting side of the skincontacting element 24 can adhere the skin contacting element 24 to thesubject's skin. The skin contacting gasket 36 can surround the tissuesite 20 to promote an air-tight seal between the skin contacting element24 and the subject's skin around the tissue site 20. The cosmetic liquidor cream, which is located within the cosmetic pad 18 in the illustratedembodiment, is then brought into contact with the tissue site 20 bytraveling through the openings 34.

The reactor housing element release layer 120 can be removed from thereactor housing element 14. Removal of the reactor housing elementrelease layer 120 from the reactor housing element 14 can expose thereactor 16 to air by removal of the lower layer 96, the seal layer 102,or the reactor housing element release layer 120 may be affixed in anair-tight manner to the reactor housing element 14 so that air isprecluded from access to the reactor 16 until after the reactor housingelement release layer 120 is removed from the reactor housing element14. After removal of the reactor housing element release layer 120 fromthe reactor housing element 14, the lower surface 56 of the reactorhousing element 14 can be brought in contact with an upper surface 152of the liquid impermeable-air permeable membrane 150, which can have itslower surface 154 affixed to the interface side 32 of the skincontacting element 24. Alternatively, where the liquid impermeable-airpermeable membrane 150 is positioned between the reactor substrate 80and the lower layer 96, the lower surface 56 of the reactor housingelement 14 can be brought in contact with the interface side 32 of theskin contacting element 24. When the reactor housing element 14 isbrought into contact with the liquid impermeable-air permeable membrane150 and/or the skin contacting element 24, the reactor 16 consumes theselected gas found within the enclosed volume 22. A chemical reactionoccurs where heat can be generated, and a pressure reduction withrespect to atmospheric pressure occurs by consumption of the selectedgas. The reactor 16 can heat the enclosed volume 22 above ambient, whichcan provide a therapeutic effect for use with some cosmetic liquids orcreams. In addition, suction can be applied to the tissue site thusstretching the subject's skin at the tissue site, which can also have atherapeutic effect with certain cosmetic liquids or creams. Moreover,the application of topical negative pressure at a particular tissue sitecan also have a therapeutic effect.

The controlled pressure device 10 can be designed with certainparameters. As an example, assuming the tissue site 20 of about 10 cm×20cm and an offset of the hood 50 (or the top of the reactor housingelement 14) of about 2.5 cm from the tissue site 20 results in theenclosed volume 22 of 500 mL. Assuming that the cosmetic liquid or creamand the solid components of the cosmetic pad 18 in addition to thereactor 16 and any other solid components (e.g., the liquidimpermeable-air permeable membrane 150) within the enclosed volume 22account for 100 mL within the enclosed volume 22, this leaves 400 mL airin the enclosed volume. 400 mL of air results in about 320 mL ofnitrogen and 80 mL of oxygen within the enclosed volume 22 prior to theapplication of a partial vacuum resulting from the reactor 16 consuminga selected gas in the air within the enclosed volume 22. One gram (1 g)of zinc (Zn) will consume about 170 mL at standard temperature andpressure (STP) of oxygen (02), which is the amount of oxygen in about850 mL (STP) of normal dry air. Although the skin contacting gasket 36and the reactor housing element gasket 60 can be provided, there willlikely be leakage of ambient air into the enclosed volume 22 past thegaskets 36, 60 and possibly diffusion through the reactor housingelement 14 and the skin contacting element 24. For the purposes of thisdisclosure, both leakage past interfaces (e.g., leakage around the skincontacting gasket 36) and diffusion (e.g., diffusion through the reactorhousing element 14) will be referred to as leakage. The gaskets 36, 60,the skin contacting element 24 and reactor housing element 14 areconfigured to have a maximum leakage rate of air into the enclosedvolume 22 from ambient. For example, a maximum leakage rate of 1 mL(STP)/hour of air into the enclosed volume from ambient results in 0.2mL (STP) of oxygen/hour. Since 1 g of zinc consumes 170 mL of oxygen(STP), 1 g of zinc provides an adequate amount of a reducing agent toresult in a 20% reduction from normal atmospheric pressure within theenclosed volume 22 for an extended period of time, e.g., well over 72hours. The controlled pressure device 10 will likely be worn for a muchshorter period of time and the tissue site 20 being treated may be muchsmaller than 10 cm×20 cm. It can be seen that a very small reactor 16,e.g., one able to accommodate less than 1 g of zinc, can be used in thecontrolled pressure device 10.

In view of the foregoing, the controlled pressure device 10 can beconfigured as follows. The reactor 16 can be configured to have apredetermined scavenging capacity (“SC”), which relates to the volume ofthe selected gas that the reactor 16 is configured to consume. Forexample, as mentioned above 1 g of zinc will consume about 170 mL ofoxygen (STP), so the scavenging capacity would be 170 mL. The enclosedvolume 22 can have a determined volume (“DV”) based on the area of thetissue site 20, the size of the reactor housing element 14, the offsetof the hood 50 (or top of the reactor housing element 14) from thetissue site 20, taking into account the cosmetic liquid or cream and thesolid components of the cosmetic pad 18 in addition to the reactor 16and any other solid components within the enclosed volume 22. Forexample, the determined volume of 400 mL was discussed above. Also, thecontrolled pressure device 10 can be configured to have a maximumleakage rate (LR) for air entering the enclosed volume 22. In addition,the controlled pressure device 10 can be configured to have a minimumwear time (“MWT”), which relates to the minimum amount of time that thecontrolled pressure device 10 is configured to be worn. Assuming that itis desirable to have the reactor 16 consume, or scavenge, the selectedgas for the entire minimum wear time, the controlled pressure device canbe configured in view of the following relationship:

SC>DV*(% of selected gas in air)+LR*(% of selected gas in air)*MWT.

The scavenging capacity can be determined to provide a relatively smallreactor 16 in relation to the reactor housing element 14 and the tissuesite 20 to be treated. The determined volume can be determined toprovide a relatively small reactor 16 and reactor housing element 14 inview the tissue site 20 to be treated. The maximum leakage rate for airentering the enclosed volume 22 should be reduced as much as ispractical; however, there may be some circumstances in which apredetermined amount of leakage is desirable, for example where cyclingof pressure within the enclosed volume 22 is desired. For example, themaximum leakage rate for air entering the enclosed volume 22 can be lessthan 10 mL/hour, and preferably less than 1 or 2 mL/hr. The minimum weartime can be determined based on the desired amount of time the topicalnegative pressure is to be applied to the tissue site 20. It may bedesirable to include a safety factor (e.g., a multiplier on the rightside of the relationship above) to accommodate for manufacturingtolerances, differences among tissues sites and subjects placing thecontrolled pressure device 10 on the tissue site 20.

As the reactor 16 consumes the selected gas found in air within theenclosed volume 22, an exothermic reaction occurs such that there is anincrease in temperature of the reactor 16. As such, the reactor 16 canoperate as a heater to heat the cosmetic liquid or cream impregnated inthe cosmetic pad 18. This can change the viscosity of the cosmeticliquid or cream, which can facilitate entry of the cosmetic liquid orcream into skin pores.

The reactor housing element 14 could also be provided with a removablesection 160 that when removed could provide ambient air access to thereactor 16 or an additional reactor located beneath the reactor housingelement 14. For example, the removable section 160 can be affixed to theupper layer 94 of the package in which the reactor substrate 80 islocated. Removal of the removable section 160 can result in removal ofat least a portion of the upper layer 94 thus exposing the reactorsubstrate 80 to ambient air, which would result in an exothermicreaction. Alternatively, an additional reactor could be located beneaththe reactor housing element 14 and removal of the removable section 160can result in removal of at least a portion of the package (similar tothe package made up of the upper layer 94 and the lower layer 96) thusexposing the additional reactor to ambient air. The additional reactorcan also heat the gas in the enclosed volume 22, which can heat thetissue site 20.

Different types of reactors could be used to provide topical negativepressure inside the enclosed volume 22 of the controlled pressure device10. FIG. 3 depicts multiple reactor substrates or multiple regions onthe same reactor substrate, which are depicted as reactor elements 80 a,80 b and 80 c each having different chemical properties and/orcharacteristics. For example, the first reactor element 80 a can beconfigured to begin consuming oxygen after being exposed to oxygen for avery short (first) period of time t1, e.g., nearly instantaneously. Thesecond reactor element 80 b can be configured to begin consuming oxygenafter being exposed to oxygen for a longer (second) period of time t2,and the third reactor element 80 c can be configured to begin consumingoxygen after being exposed to oxygen for an even longer (third) periodof time. Alternatively, the second reactor element 80 b can beconfigured with a delayed reaction time to begin consuming oxygen afterthe first reactor element 80 a has been exhausted and no longer consumesoxygen. Similarly, the third reactor element 80 c can be configured witha delayed reaction time to begin consuming oxygen after the firstreactor element 80 a and the second reactor element 80 b have both beenexhausted and no longer consume oxygen. Such a configuration can allowfor a cycling of pressure in the enclosed volume 22.

In lieu of the reactor 16 made up of the reactor substrate 80, thereactor 16 may be one or any combination of a zinc-based chemical pump,electro-chemical pumps, vacuum-on-demand devices (referred to herein asVOD), electrolyzers, pressure-reducing solid state devices, oxygenabsorbing iron packets, or getters of zirconium titanium, vanadium iron,lithium, lithium metal, magnesium, calcium, lithium barium combinations,zinc-air battery, zinc-air battery components or other materials highlyreactive with the selected gases, for example, nitrogen, carbon dioxideand oxygen gases found in skin tissue environments.

FIG. 4 depicts another reactor 226 that can be used in place of thereactor 16 shown in FIG. 1. WO 2015/054040 A1, which is incorporated byreference, describes an electrochemical cell that is adapted to consumegases, i.e., air or its gaseous non-noble constituents, within anenclosure via an electrochemical reaction. This consumption of gaswithin a sealed enclosure forms a partial vacuum. The controlledpressure device 10 can include such a reactor 226 having anelectrochemical cell 228 that lowers the pressure within the enclosedvolume 22 through an electrochemical reaction that takes place when avoltage is applied to the electrochemical cell 228 by a power source 230(depicted schematically in FIG. 4). Operation of electrochemical cell228 in this example can also be achieved by controlling the currentsupplied to the electrochemical cell 228 by the power source 230, forexample by providing a switch 232 that can be operated by the user. Thepower source 230 can be located in the enclosed volume 22 or be providedoutside the controlled pressure device 10 (e.g. on the reactor housingelement 14). The switch 232 can be provided outside the controlledpressure device 10 (e.g. on the reactor housing element 14).

In an example where the reactor is a VOD device, a VOD is a solid stateelectrochemical cell, which when charged with a low voltage, produces ahighly reactive material that captures gases present in the atmosphereand when sealed in an air tight system can form a partial vacuum. In aVOD device, metal is deposited to grow dendrites as a voltage is appliedacross electrodes of the VOD device and lithium salt electrolyte,charging the VOD device. Similar to charging a battery, electrons aremoved from layer to layer to form metallic lithium.

In an example where the reactor is a getter, a getter, as known in theart, is a deposit of reactor material that is used for initiating andmaintaining a partial vacuum. When gas molecules strike the gettermaterial, particular gas molecules (i.e., those of the selected gas)combine with the getter chemically or by adsorption. Thus the getterremoves the selected gas from the evacuated space until the activematerial is exhausted.

A reactor having a self-regulating oxygen getter powered by zinc-airbattery technology may be used in lieu of the above-described reactor 16made up of the reactor substrate 80. Zinc-air batteries can react tocontrol or reduce the oxygen levels in sealed site and thusself-regulate a reduced pressure of approximately 0.8 bars. If thezinc-air battery components are configured as a working zinc-airbattery, the battery voltage will drop when the oxygen has been depletedand the desired partial vacuum pressure will have been achieved. Thisdrop in voltage may be used to indicate that the desired partial vacuumhas been achieved. For example, a 675 size hearing aid zinc-air batteryis rated at 620 mAh, occupies 0.5 mL volume, and weighs 1.9 g. A 675zinc-air battery can remove more than 150 times its volume of oxygen.

The cosmetic pad 18 can be made from a blend of polyester and cellulosefibers, polypropylene fibers, or other suitable non-woven polymericmaterial. The cosmetic liquid or cream can include at least one of amoisturizer, dimethylaminoethanol (DMAE), Acetyl hexapeptide-8, Acetylhexapeptide-3, retinol, ubiquinone, dithiolane-3-pentanic acid,alpha-hydroxy acid, alpha lipoic acid, salicylic acid, hydrocortisone,topical botulinum cream, and hyaluronic acid. The cosmetic pad 18 caninclude top surface 180 and a bottom surface 182, which is opposite thetop surface 180. The bottom surface 182 can be undulated having hills184 and valleys 186, which can allow the cosmetic pad 18 to act as askin massaging element. An additional membrane 188 could be provided andlocated beneath the cosmetic pad 18 to act as the skin massagingelement. This additional membrane 188 would also be positioned adjacentto the tissue site 20. This additional membrane 188 could also includean undulated bottom surface, similar to the bottom surface 182 havinghills 184 and valleys 186. This additional membrane 188 would alsoinclude openings to allow the cosmetic liquid or cream to pass throughthe openings to the tissue site 20. When a partial vacuum is provided inthe enclosed volume 22, the skin can be drawn towards the undulatedsurface and the skin can conform to the hills 184 and valleys 186.Accordingly, small strains and stresses can applied to the patient'sskin at the tissue site 20 providing a massaging effect.

The controlled pressure device 10 can also include additional poweredcomponents, which is shown as a powered component 240 that isschematically depicted in FIG. 2. Each powered component 240, which aredescribed later with reference to FIGS. 5-7, can be electricallyconnected with a power source 242 (depicted schematically in FIG. 2)which, for example, can be a zinc-air battery exposed to ambient or azinc MnO2 battery, electrically connected with the powered component240. When using a zinc-air battery as the power source 242, the powersource 242 would be located outside of the enclosed volume 22 or asection of the reactor housing element 14 or the skin contacting element24 could be removable to allow ambient air to contact the zinc-airbattery.

FIG. 5 depicts a heater 250, which is one example of a powered component240 that can be used in the controlled pressure device 10, electricallyconnected with the power source 242. The heater 250 can be a thin filmheater or thin film nano wire heater. The heater 250 can heat thecosmetic liquid or cream impregnated in the cosmetic pad 18. The heater250 can be positioned adjacent to the cosmetic pad 18. A switch 252 canbe provided to control power to the heater 250. The heater 250 can alsoheat the gas in the enclosed volume 22, which can heat the tissue site20.

FIG. 6 depicts a first electrode 260 and a second electrode 262electrically connected with the power source 242. The electrodes areanother example of a powered component 240 that can be used in thecontrolled pressure device 10. The switch 252 can be provided to controlpower to the electrodes 260, 262. The first electrode 260 can bepositioned on a first side of the tissue site 20 and in contact with theskin, and the second electrode 262 can be positioned on a second,opposite, side of the tissue site 20 and in contact with the skin. Theelectrodes 260, 262 can be used to provide electrical stimulation to thetissue site 20.

FIG. 7 depicts a light source 280, which is another example of a poweredcomponent 240 that can be used in the controlled pressure device 10. Thelight source 280 can include a plurality of LEDs 282 mounted on aflexible substrate 284. The LEDs 282 are electrically connected with thepower source 242. The flexible substrate 284 can be placed adjacent tothe skin contacting element 24, which can include larger openings 34,which can allow light to pass for phototherapy.

FIG. 8 depicts a method of treating tissue using negative pressure.Although the FIG. 8 shows a specific order of method steps, the order ofthe steps may differ from what is depicted. Also two or more steps maybe performed concurrently or with partial concurrence. The method willbe described with reference to the controlled pressure device 10depicted in FIGS. 1 and 2, however, the method can be practiced withother devices.

At 300, the reactor housing element release layer 120 is removed fromthe reactor housing element 14. Removal of the reactor housing elementrelease layer 120 from the reactor housing element 14 can allow air tocontact the reactor 16, which can begin the reaction in which oxygen (oranother selected gas in air) is being consumed by the reactor 16. At302, the reactor housing element 14, the reactor 16 and the liquidimpermeable—air permeable membrane 150 are placed over the tissue site20. At 304, the reactor housing element 14 is affixed with respect tothe skin around the tissue site 20 to define an at least substantiallyair-tight enclosed volume 22 around the tissue site. The reactor 16 canconsume the selected gas (e.g., oxygen) from the enclosed volume 22 thusreducing the gas pressure in the enclosed volume 22.

FIG. 9 depicts other steps in a method of treating tissue using negativepressure. For example, the method may include, at 310, placing acosmetic liquid or cream on the tissue site 20. The cosmetic liquid orcream may be placed on the tissue site 20 prior to placing the reactorhousing element 14, the reactor 16 and the liquid impermeable—airpermeable membrane 150 over the tissue site 20, which occurs at step302.

The method of treating tissue using negative pressure may also include,at 312, placing a pad 18 impregnated or wetted with a cosmetic liquid orcream over the tissue site 20. The pad 18 can be connected with thereactor housing element 14 in such a manner that the pad 18 is placed onthe tissue site 20 while placing the reactor housing element 14, thereactor 16 and the liquid impermeable—air permeable membrane 150 overthe tissue site 20.

The method of treating tissue using negative pressure may also include,at 314, removing the release layer 40 from the skin contacting element24, and, at 316, placing the skin contacting element 24 over or aroundthe tissue site 20. The skin contacting element 24 can be placed over oraround the tissue site 20 prior to placing the reactor housing element14, the reactor 16 and the liquid impermeable—air permeable membrane 150over the tissue site 20, which occurs at step 302. As such, affixing thereactor housing element 14 with respect to skin around the tissue site,which occurs at step 304, can further include affixing the reactorhousing element 14 to the skin contacting element 24, at 318. The methodmay also include affixing the skin contacting element 24 to the skinaround the tissue site 20, at 320.

It will be appreciated that various of the above-disclosed controlledpressure device and other features and functions, or alternatives orvarieties thereof, may be desirably combined into many other differentsystems or applications. Also that various presently unforeseen orunanticipated alternatives, modifications, variations or improvementstherein may be subsequently made by those skilled in the art which arealso intended to be encompassed by the following claims.

1. A controlled pressure device for tissue treatment, the devicecomprising: a reactor housing element configured to at least partiallydefine an at least substantially air-tight enclosed volume around atissue site when fixed in space in relation to the tissue site; and areactor positioned in the enclosed volume and configured to react with aselected gas found in air, wherein the reactor consumes the selected gaswithin the enclosed volume.
 2. The controlled pressure device of claim1, further comprising a cosmetic liquid or cream located in the enclosedvolume.
 3. The controlled pressure device of claim 2, wherein thecosmetic liquid or cream includes at least one of a moisturizer,dimethylaminoethanol (DMAE), Acetyl hexapeptide-8, Acetyl hexapeptide-3,retinol, ubiquinone, dithiolane-3-pentanic acid, alpha-hydroxy acid,alpha lipoic acid, salicylic acid, hydrocortisone, topical botulinumcream, and hyaluronic acid.
 4. The controlled pressure device of claim2, further comprising a pad impregnated with the cosmetic liquid orcream.
 5. The controlled pressure device of claim 1, wherein the reactorincludes a reactor substrate, a reducing agent, a binder, and anelectrolyte solution.
 6. The controlled pressure device of claim 1,further comprising a release layer adhered to a lower surface of thereactor housing element, wherein the release layer provides an air-tightbarrier such that air is precluded from access to the reactor untilafter the release layer is removed from the reactor housing element. 7.(canceled)
 8. The controlled pressure device of claim 1, furthercomprising a package including a plurality of air-tight barriersselectively removable from the package, wherein the reactor ispositioned within the package and the selected gas is precluded fromaccess to the reactor until after at least one of the plurality ofair-tight barriers is removed from the package.
 9. The controlledpressure device of claim 1, wherein the reactor includes a plurality ofreactor elements is-configured to cycle gas pressure in the enclosedvolume, wherein the plurality of reactors includes a first reactorelement configured to begin consuming oxygen after being exposed tooxygen for a first period of time and a second reactor elementconfigured to begin consuming oxygen after being exposed to oxygen for asecond period of time, which is greater than the first period of time.10. (canceled)
 11. (canceled)
 12. (canceled)
 13. The controlled pressuredevice of claim 1, further comprising a skin contacting elementincluding a skin contacting side for contacting a subject's skin,wherein the skin contacting element includes an opening extendingthrough the skin contacting element from the skin contacting side to aninterface side, which is opposite to the skin contacting side.
 14. Thecontrolled pressure device of claim 13, wherein the reactor housingelement affixes to the interface side of the skin contacting elementproviding a substantially air-tight seal between the reactor housingelement and the skin contacting element.
 15. The controlled pressuredevice of claim 14, further comprising an air-tight barrier selectivelyremovable from the reactor housing element, wherein the reactor ispositioned between the reactor housing element and the air-tight barrierand the selected gas is precluded from access to the reactor until afterthe air-tight barrier is removed from the reactor housing element. 16.(canceled)
 17. The controlled pressure device of claim 1, wherein thereactor housing element includes a hood and a lower peripheral sectionat least partially surrounding the hood, the reactor housing elementbeing configured such that a downward force on the hood results in anoutward force on the lower peripheral section.
 18. The controlledpressure device of claim 1, further comprising a liquid impermeable—airpermeable membrane interposed between the reactor and the tissue sitewhen the reactor housing element is fixed in space in relation to thetissue site.
 19. The controlled pressure device of claim 1, furthercomprising a cosmetic liquid or cream located in the enclosed volume anda liquid impermeable—air permeable membrane interposed between thereactor and the cosmetic liquid or cream.
 20. The controlled pressuredevice of claim 1, further comprising a pressure relief valve on thereactor housing element, wherein the pressure relief valve allows forselective communication between the enclosed volume and ambient.
 21. Thecontrolled pressure device of claim 1, wherein the controlled pressuredevice is configured to allow an operator to change the size of theenclosed volume while the reactor consumes the selected gas in theenclosed volume.
 22. (canceled)
 23. (canceled)
 24. The controlledpressure device of claim 1, wherein the reactor is configured having apredetermined scavenging capacity (SC) for the selected gas, wherein theenclosed volume has a determined volume (DV), the controlled pressuredevice is configured to have a maximum leakage rate (LR) for airentering the enclosed volume, and the controlled pressure device isconfigured to a minimum wear time (MWT) wherein:SC>DV*(% of selected gas in air)+LR*(% of selected gas in air)*MWT. 25.The controlled pressure device of claim 1, wherein the reactor is one orany combination of a zinc-based chemical pump, an electro-chemical pump,a vacuum-on-demand device, an electrolyzer, a pressure-reducing solidstate device, an oxygen absorbing zinc or iron packet, a zinc-airbattery, a zinc-air battery component and a getter of zirconiumtitanium, vanadium iron, lithium, lithium metal, magnesium, calcium,lithium barium combinations.
 26. The controlled pressure device of claim1, wherein the reactor is configured to consume ambient oxygen to heatcosmetic liquid or cream in the enclosed volume.
 27. The controlledpressure device of claim 1, wherein the reactor is configured to consumeoxygen within the enclosed volume to reduce gas pressure within theenclosed volume, and the controlled pressure device further comprisingan additional reactor configured to consume ambient oxygen to heatcosmetic liquid or cream in the enclosed volume.
 28. (canceled) 29.(canceled)
 30. The controlled pressure device of claim 1, furthercomprising a skin massaging element positioned in the enclosed volume,wherein the skin massaging element is positioned adjacent to the tissuesite when the skin contacting side of the skin contacting element is incontact with a subject's skin, wherein the skin massaging elementincludes an undulated bottom surface.
 31. (canceled)
 32. The controlledpressure device of claim 30, wherein the skin massaging element is amembrane including openings through which cosmetic liquid or creampasses. 33-72. (canceled)